Portable outdoor enclosure having windows with one-way mirror effect

ABSTRACT

A collapsible and portable enclosure, for providing covering concealment to a user, includes one or more flexible plastic window panels which function as one-way mirrors during daylight hours. The enclosure includes a fabric cover having at least one side wall, and a support structure for supporting the fabric cover. The support structure may include a plurality of collapsible hub-and-strut assemblies. The fabric cover has at least one window opening formed through the side wall, and a flexible panel extending across the window opening. The flexible panel has a partially reflective exterior surface which partially reflects light and partially transmits light, allowing the flexible panel to effectively function as a one-way mirror. Optionally, the flexible panel may be removable and replaceable, allowing a hunter to shoot through the panel and to replace it later.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 USC § 119 based on U.S. provisional application No. 60/844,141, filed on Sep. 12, 2006. The entire subject matter of this priority document is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to portable outdoor enclosures, such as hunting blinds. More particularly, the present invention relates to a portable outdoor enclosure having one or more windows, with a flexible panel serving as a one-way mirror in some or all of the windows.

2. Description of the Background Art

When out in the field for moderate or long periods, hunters often spend time in hunting blinds to disguise themselves from game, and also to protect themselves from inclement weather. However, a problem arises because the hunting blind or shelter is an unnatural object, and its unusual shape and colors tend to make it stand out when viewed by wild game. As a result, game generally avoids the blind or shelter, and the hunter's position is compromised.

Similarly, naturalists, nature photographers, and environmental scientists often work out in the field, such as in forest or wilderness areas. Naturalists often wish to approach and view wild animals as closely as possible without being detected, in order to photograph or observe the animals in their natural habitat, while disturbing them as little as possible. Accordingly, these people also find it useful to disguise their presence while also being sheltered from the elements of nature.

Many designs for hunting blinds are known. Class 135, subclass 901 is provided in the U.S. Patent Classification System for the listing of hunting blinds and ice fishing shelters.

Adams, U.S. Pat. No. 6,009,673 discloses a portable insulated modular shelter, which is usable as a hunting blind, ice fishing shelter, or wildlife observatory. Several other known designs for hunting blinds, ice fishing shelters and similar enclosures are referred to and discussed in the background section of the Adams '673 reference.

Collapsible, foldable, and easily disassembled frame structures are known. Examples of such structures are disclosed in U.S. patents to Beavers (U.S. Pat. No. 3,810,482), Foster (U.S. Pat. No. 4,938,243), and Stumbo (U.S. Pat. No. 5,628,338). Each of these patents show collapsible frames used to support a flexible covering for use as tents, blinds, or other shelters. Beavers and Stumbo each show frames which include support poles extending from a central hub, and Stumbo discloses a frame structure in which includes several sub-frames, each of which supports a portion of a flexible covering.

Many flexible coverings used in known collapsible enclosures are supported by the frame structures to provide the outer shell of the enclosure, and are commonly made of fabric. The flexible coverings normally include at least one door opening and one or more window openings. Window openings may be vacant, or alternatively, may be covered with transparent sheeting, screen, a closeable flap, or combinations thereof. Examples of such coverings are disclosed in U.S. patents to Smith (U.S. Pat. No. 3,709,237) and to Husted (U.S. Pat. No. 4,067,346), which each disclose respective fabric extensions at a lower edge of a covering, for use in securing the covering to the ground.

A variety of approaches have been used in the prior art to stabilize a collapsible enclosure in a desired location, in all types of weather environments. A common strategy is to stake the enclosure to the ground, either by securing a lead line between a buried stake and the enclosure, or by staking the flexible covering directly to the ground. A variety of tent stakes are known, for implantation in a variety of soil types. U.S. patent D 363,755 to Diederich depicts a tent stake including a threaded shaft.

Although the known devices have some utility for their intended purposes, a need still exists in the art for an improved hunting blind, which will tend to blend in to the surroundings, and thereby tend to escape notice by local animals, particularly game animals.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a portable outdoor enclosure for covering and concealing a hunter or naturalist in a field setting, in which an occupant of the enclosure can see out, while animals outside of the enclosure cannot see the occupant.

A collapsible and portable enclosure, according to a selected illustrative embodiment, includes one or more flexible plastic window panels which function as one-way mirrors during daylight hours. The enclosure includes a fabric cover having at least one side wall, and a support structure for supporting the fabric cover. The support structure may include a plurality of collapsible hub-and-strut assemblies.

The fabric cover has at least one window opening formed through the side wall, and the enclosure also includes a flexible panel extending across the window opening. The flexible panel has a partially reflective exterior surface which partially reflects light and partially transmits light, allowing the flexible panel to effectively function as a one-way mirror.

The flexible panel may include a plastic film material which includes polyester.

Optionally, the flexible panel may be provided as part of a removable and replaceable modular unit, allowing a hunter to shoot through the panel and to conveniently replace it later.

For a more complete understanding of the present invention, the reader is referred to the following detailed description section, which should be read in conjunction with the accompanying drawings. Throughout the following detailed description and in the drawings, like numbers refer to like parts.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an elevated perspective view of an assembled portable outdoor enclosure according to a first illustrative embodiment of the present invention, showing internal sub-frames and tensioning straps in phantom.

FIG. 1B is a perspective view is a perspective view showing another side of the collapsible portable enclosure of FIG. 1, with an occupant of the enclosure shown in phantom;

FIG. 1C is a perspective view showing an interior portion of the enclosure of FIGS. 1A-1B, illustrating the ability of the occupant to see the environment outside of the enclosure;

FIG. 2 is a top perspective view of the internal frame structure of the enclosure of FIG. 1, with the covering deleted from the drawing for illustrative purposes.

FIG. 3A is a detail view of a lower corner of the covering portion of the enclosure, showing the end portion of the skirt from one sidewall extending laterally outwardly beyond the sidewall, and the end portion of the skirt from an adjacent sidewall arranged to overlap it.

FIG. 3B is a detail view of the lower corner of the covering similar to FIG. 3, showing the respective end portions layered such that the grommets lie in vertical alignment, and showing, in an exploded manner, a stake positioned for insertion through the aligned grommets.

FIG. 4 is a detail internal view of a window portion of the enclosure of FIG. 1, showing a removable modular window unit spaced away from a wall of the enclosure.

FIG. 5 is an exploded detail view showing the components of one sub-frame of the frame structure of FIG. 2, including the hub, the hub cap plate, and the poles.

FIG. 6 is a detail view of the hub portion of the sub-frame of FIG. 3, viewed from a vantage point inside of the shelter.

FIG. 7 is a detail view of a corner of a sidewall of the structure of FIG. 1 as viewed from the inside of the shelter, showing the distal end of a pole secured to the inner surface of the covering by insertion within a pocket formed on the inner surface of the covering.

FIG. 8 is a perspective view of a stake used for attaching the structure of FIG. 1 to a supportive substrate, illustrating the threaded lower end, a handle formed on the upper end, and a wide flange provided between the upper end and lower end.

FIG. 9 is a detail view of the of the lower tip end of the stake of FIG. 8, showing the helical shape of the lower end, and the angle θ of the terminal tip relative to the longitudinal axis of the stake.

FIG. 10 is a perspective view of the tensioning mechanism isolated from the tensioning straps, showing the textured bar overlying the base plate; and

FIG. 11 is a side view of the tension-producing member, showing the tensioning straps extending from the tensioning mechanism.

DETAILED DESCRIPTION

It should be understood that only structures considered necessary for clarifying the present invention are described herein. Other conventional structures, and those of ancillary and auxiliary components of the system, are assumed to be known and understood by those skilled in the art.

First Embodiment Overview

A selected illustrative embodiment of an inventive portable outdoor enclosure according to the present invention will now be described, with reference to the drawings. As shown in FIG. 1, in a fully assembled configuration thereof, a portable outdoor enclosure 10 according to the selected embodiment includes a flexible outer covering or shell 20, supported by a frame 70, and secured to a supportive substrate 5 using a plurality of anchor stakes 130.

The covering 20 is cooperatively supported by, and overlies the frame 70. The covering 20 provides an outer shell for the portable enclosure 10, and is formed of a flexible sheet material. In the illustrated embodiment, the flexible sheet material is a woven synthetic fabric to provide the durability, flexibility and strength required for use in harsh environmental conditions.

The covering 20 includes a plurality of interconnected sidewalls 22 and a roof 24. The sidewalls 22 are arranged in a lateral edge-to-edge relationship, such that each of the sidewalls 22 is joined to an adjacent sidewall at each of its respective lateral edges, to form a closed section. The roof 24 is joined, at its peripheral edges, to the respective upper edges of the sidewalls 22, to close the upper end of the portable enclosure 10. The lower end of the portable enclosure 10 may be left open to allow the user to have access to substantially the entire ground surface area within the surrounding sidewalls, or alternatively, if desired, a floor 25 (FIG. 1C) may be provided extending across the enclosure at the bottom of the sidewalls 22.

Alternatively, if desired, a bag used to house and store the enclosure in a collapsed configuration thereof may be adapted to be used as a floor in the assembled configuration of the enclosure, to cover part or all of the floor area inside of the enclosure.

The Outer Shell

In the first illustrative embodiment of the invention, shown in FIGS. 1A-1C, the covering 20 of the enclosure 10 consists of four sidewalls 22 and a roof 24. However, it is within the scope of the invention to use only three sidewalls, or more than four sidewalls. For example, for a larger enclosure, five or six sidewalls may be provided. Alternatively, a cylindrical or dome-shaped structure may be provided with a single side wall extending around the entire structure.

One or more of the sidewalls 22 may be provided with a window opening 28. A flexible sheet insert 30 may be either sewn on to or removably placed over the window opening 28, either on the inside or the outside of the covering 20, to allow natural light to enter into the interior space within the portable enclosure 10, while substantially keeping insects out.

The sheet insert 30 includes a flexible plastic window panel 31 which functions as a one-way mirror during daylight hours. The flexible panel 31 has a partially reflective exterior surface which partially reflects light and partially transmits light, allowing the flexible panel to effectively function as a one-way mirror. The flexible panel 31 may include a plastic film material which includes polyester and which may be formed of, or may include a polyester film sold by the DuPont Corporation under the trademark MYLAR.

Referring now to FIG. 1C, it is noteworthy that the game animal on the outside of the enclosure cannot see into the enclosure because of the one-way mirror effect of the window panel, yet the occupant of the enclosure can see outwardly through the window panel and can view the animal.

The sheet insert 30 may be made removable so that if a hunter is obligated to shoot through it with a gun or arrow, the damaged sheet insert may be replaced at a later time. Where a removable sheet insert 30 is used, as shown in FIG. 4, a first window frame strip 29 may be attached to the covering 20 surrounding the window opening 28, and this first window frame strip 29 may be formed of a loop-type material of a hook-and-loop fastener of the type commonly referred to as VELCRO. A second, corresponding window frame strip 32 may be made part of the sheet insert 30, as shown, and this second window frame strip may be formed of a hook-type material to allow it to removably engage the loop-type material of the first window frame strip 29. Optionally, other alternate removable sheet inserts may be provided with permeable screen material extending thereacross, for use in warmer weather for ventilation.

The sheet insert 30 may be covered with a selectively movable flexible window flap (not shown) inside or outside of the enclosure. If desired, only a portion of one edge of the sheet insert 30 may be fixed to a corresponding edge of the window opening 28 so as to allow the sheet insert 30 to be selectively openable. A selectively openable sheet insert 30 may also be layered over a screen insert (not shown).

The portable enclosure 10 includes at least one selectively closable door opening 36 formed in a sidewall 22, to permit ingress into, and egress from the enclosure 10. In the depicted embodiment, the door opening 36 is a closable door flap 38 that is secured to the sidewall 22 using conventional door closure means 40, which may include, but is not limited to, hook and loop fasteners, zippers, snaps, or ties.

A vent opening 42 may be formed in the roof 24, and comprises a breathable vent insert 43 sewn therein which prevents environmental precipitation from entering into the interior of the enclosure 10, and which also allows adequate ventilation of the structure. The vent opening 42 may include a closable flap of fabric on the interior of the covering 20, and a screen panel may be provided as the vent insert 43.

The lower edge 44 of each sidewall 22 may have a skirt portion 50 attached thereto along the entire width thereof, and where used, the outer ends of skirt portion may be made to extend beyond the sidewall 22 at each side thereof. The skirt portion 50 is an elongate rectangular band formed of the same material as the tent body, and has a width that is greater than the width of the sidewall 22. The skirt portion 50 extends continuously along the entire lower edge 44 of the sidewall 22 such that the respective ends 54 of the skirt portion 50 extend beyond both lateral edges of the sidewall 22 (FIG. 3A). Each end 54 of the skirt portion 50 is provided with a through hole 58. The edges of the through hole 58 are reinforced. In the illustrated embodiment, the through hole 58 is reinforced with a metal or high-strength plastic grommet 60.

In the assembled configuration of the enclosure 10, the sidewalls 22 extend substantially vertically upwardly, with each sidewall bowed slightly outwardly by its respective sub-frame 72 (FIG. 2), and the skirt portion 50 for each sidewall 22 extends out parallel to the substrate 5 and perpendicular to the sidewall 22, so as to overlie and confront the surface of the substrate 5.

As shown in FIGS. 3-4, in the assembled configuration of the enclosure, the respective end flaps of adjacent skirt portions overlap one another at the corners of the covering 20, to provide a strong support for the enclosure when the overlapped end flaps are attached to the substrate 5. At the corners of the portable enclosure 10, the respective ends 54 of the skirt portions 50 for adjacent sidewalls are arranged to lie in a layered, overlapping relationship. That is, the end 54 of the skirt portion 50 of one sidewall 22 overlies the end 54′ of the skirt portion 50′ of the adjacent sidewall 22′, so that the through hole 58 of the end 54 of the skirt portion 50 of the one sidewall overlies and is in vertical alignment with the through hole 58′ of the end 54′ of the skirt portion 50′ of the adjacent sidewall 22′, to form a vertically aligned through hole pair 66. Each through hole 58 of the through hole pair 66 is sized to receive the shank 134 of the anchor stake 130 therethrough, and has a diameter which is smaller than the diameter of the anchor stake's flange 136.

The Frame

Referring now to FIG. 2, the frame 70 cooperates with the covering 20 to provide a three-dimensional enclosure which is free standing, lightweight, and easily assembled and disassembled. In the depicted embodiment of the enclosure 10, the frame 70 includes five sub-frames 72 such that a separate sub-frame 72 is provided for the roof 24, and a sub-frame is also provided for each of the four respective sidewalls 22. In the embodiment of FIGS. 1-2, the individual sub-frames 72 are not connected to one another. When assembled with the covering 20, the individual sub-frames 72 are discontiguous with each other.

Each sub-frame 72 includes a substantially cylindrical central hub 74, and further includes a plurality of poles 76, which are pivotally mounted to the hub 74 and extend outwardly therefrom. In the illustrated embodiment, four poles 76 are provided for each hub. However, it is within the scope of this invention to provide a hub having a fewer or greater number of poles 76. For example, a greater number of poles 76 might be required to accommodate a non-rectangular sidewall 22.

As seen in FIGS. 5 and 6, the hub 74 is a substantially cylindrical block, which is formed from a strong, substantially solid plastic or metal material having a number of openings formed therein, as will be further described. The hub 74 has an outer face 92 for placement facing toward the interior of the portable enclosure 10, and an inner face 94 for placement against the interior surface of the covering 20, when the portable enclosure is assembled. The hub 74 has an arcuate peripheral edge surface 96 extending between the inner face 94 and the outer face 92.

The hub 74 also has a plurality of mounting apertures 98 formed therein. One mounting aperture 98 is provided for each pole 76. The mounting apertures 98 are positioned so as to surround, and be equidistantly spaced about, the axial centerline of the hub 74. Each mounting aperture 98 includes a shaped through hole 99 and a radial groove 100 extending from a respective through hole 99. The through holes 99 extend through the block of the hub 74, between the inner face 94 and the outer face 92. The inner surface of each through hole 99 is irregularly shaped, and includes both a pair of opposed key slots 102 and a stop slot 116. The hub 74 has a stop surface 118 formed therein at a lower end of the stop slot 116.

Each mounting aperture 98 further includes a plurality of radially extending grooves 100 formed in the outer face 92 thereof. Each of the radial grooves 100 extends radially inwardly from the peripheral edge surface 96 so as to terminate at and communicate with a respective mounting aperture 98. In the illustrated embodiment, four poles 76 are provide for each hub 74, and thus each hub 74 includes four mounting apertures 98.

Each pole 76 consists of an elongate semi-rigid rod having a shaped hub end 164 for mounting within the mounting apertures 98, and a distal end 166 opposed to the hub end 164. The rod may be made of a strong, flexible material such as plastic, a carbon composite tube, or fiberglass. The hub end 164 of each pole 76 includes a transversely extending pin which forms a key 110 positioned adjacent to the terminus of the hub end 164, and also includes a narrow, outwardly extending stop 114 formed on the terminus of the hub end 164. During assembly and in use, the key 110 is received within and pivotably supported by the key slots 102 of the through hole 99. Likewise, the stop 114 is supported by the stop surface 118 in the stop slot 116 of the through hole 99.

Once assembled, each pole 76 is positioned within the hub 74 such that the hub end 164 resides within a mounting aperture 98. Specifically, in the unfolded and opened position of the sub-frame 72 shown in FIGS. 2 and 6, the key 110 resides within the key slots 102, the stop 114 abuts the stop surface 118, and the hub end of the pole 76 resides within a corresponding radial groove 100. In this fully opened configuration, the body portion 108 of the pole 76 extends radially outwardly from the peripheral edge surface 96 of the hub 74 (FIG. 6).

Once the poles 76 are positioned within the respective mounting apertures 98, the inner face 94 of the hub 74 is covered with a circular metal washer 104. The washer 104 includes a central hole 103, which aligns with a threaded bolt hole 120 formed through the axial centerline of the hub 74. The washer 104 is maintained on the inner face 94 of the hub 74 using a threaded bolt 106, extending through both the central hole 103 of the washer 104 and the bolt hole 120 of the hub 74, and secured with a nut 105. The inner end of the bolt 106 is looped to form an eye 130. Eye 130 provides a means for grasping the hub 74, and as shown in FIG. 1, may support a short pull strap 132 to enhance that function.

Each sub-frame 72 is cooperatively supported in space by the covering 20, such that sub-frames 72 on adjacent portions of the portable enclosure 10 are not in physical contact with one another. The distal ends 166 of each respective pole 76 are received in and supported by pockets 64 formed on the interior surface 62 of the covering 20 (FIG. 7). A pocket is provided near each corner of the roof and of each sidewall, and is aligned with a line extending between diagonally opposed corners. This configuration complements the orientation of the poles 76 as they extend outward from hub 74. Thus, the frame 70 is cooperatively engaged with the cover 20, such that each individual sub-frame 72 is supported by a portion of the covering 20, and such that the plurality of sub-frames provide support and structure to the covering 20 to result in a freestanding, three dimensional construction.

Tensioning Straps

A tensioning strap 150 may, optionally, be provided on the interior surface 62 of the covering 20 for use with one or more panels thereof. Thus one or more of the sidewalls 22 and the roof 24 of the portable enclosure 10 may be provided with a tensioning strap 150. Each tensioning strap 150, where used, includes strap sections 152, 154 which extend between a pair of opposed edges of a respective portion of the covering 20, such as a sidewall 22 or roof 24, and a centrally joined using a tensioning mechanism 160. The tensioning mechanism 160 can be of a conventional type similar to a known tensioning mechanism used in automotive safety belts, which allows a single-direction adjustment of the overall length of the straps 152, 154.

The internal structure of one example of a tensioning mechanism 160 is shown in FIGS. 10 and 11. As seen in FIG. 10, the tensioning mechanism 160 includes a base plate 162 having parallel sides and having an opening 164 formed therein. A pair of opposed side flanges 165, 166 are integrally attached to and extend upwardly from the respective parallel sides of the base plate 162. Each of the side flanges 165, 166 has a respective slot 167, 168 formed therein, oriented at an upwardly sloping angle with respect to the base plate 162. The base plate 162 includes a release flange 170 having a hole 172 formed therein. If desired, a release strap may be secured to release flange 170 using the hole 172. The tensioning mechanism 160 further includes a textured bar 174 extending between the side flanges 165, 166, with the ends 176 of the bar 174 slidably disposed in the slots 167, 168 thereof. Although the inventive portable enclosure is described is illustrated using tensioning mechanism 160, it is within the scope of this invention to use other tensioning devices, such as, but not limited to, a ratcheting tensioner.

In the tensioning strap 150 according to the present invention, a first, adjustable length strap 154 is formed of a strong, flexible material. An example of such a material includes, but is not limited to, nylon webbing. Adjustable length strap 154 has opposed first and second ends 155, 157, and is pre-threaded through the tensioning mechanism 160. A user of the apparatus is not required to remove the adjustable length strap 154 from the tensioning mechanism 160, or to re-thread the adjustable length strap 154 therethrough at any time during the life of the mechanism, under normal circumstances.

The tensioning strap 150 further includes a second, fixed length strap 152 operatively attached to the adjustable length strap 154 via the tensioning mechanism 160. The fixed length strap 152 is formed of a strong, flexible material, similar to the material of the adjustable length strap 154. The fixed length strap 152 has opposed first and second ends 151, 153. The first end 151 of the fixed length strap 152 is operatively and non-adjustably attached to the tensioning mechanism 160. This may be accomplished by passing the end of the strap around the end of the base plate 162, through the opening 164, and sewing the strap back on itself, as shown in FIG. 11. The second end 153 of the fixed length strap is operatively and non-adjustably attached to the edge portion of the sidewall (or roof).

As seen in FIG. 11, the first end 155 of the adjustable length strap 154 is fed through the opening 164 in the base plate 162 in the direction shown, passed around the bar 174 in the direction of the release flange 170, and is then fed back through the opening 164. The first end 155 of the adjustable length strap 154 is allowed to hang freely. The second end 157 of the adjustable length strap 154 is operatively and non-adjustably attached to the edge portion of the sidewall (or roof) which is opposed to the edge portion upon which the second end 153 of the fixed length strap is secured. Thus as seen in FIG. 1, the tensioning strap 150 spans a respective portion of the covering, such as a sidewall 22 or roof 24, such that the strap members 152. 154 are fixed to opposed edges of the portion of the covering.

For example, in FIG. 1, a first tensioning strap 150′ is shown on a sidewall 22 and a second tensioning strap 150″ is shown on the roof 24. Although not shown, a tensioning strap 150 may be provided on additional sidewalls 22, as needed. With respect to the first tensioning strap 150′ on the sidewall 22, the second end 153′ of the fixed length strap 152′ is fixed to the upper edge of the sidewall 22, and the second end 157′ of the adjustable length strap 154′ is fixed to the lower edge of sidewall 22. Similarly, with respect to the second tensioning strap 150″ on the roof 24, the second end 153″ of the fixed length strap 152″ is fixed to a first lateral edge of the roof 24, and the second end 157″ of the adjustable length strap 154″ is fixed to an opposed lateral edge of the roof 24.

As seen in FIG. 1, adequate tension is provided by inversion of the sub-frames in the open assembled configuration thereof, so that the distal ends 166 of each pole 76 are flexed inwardly toward the center of the portable enclosure 10, and so that the hub is pressed outwardly, away from the center of the portable enclosure 10 and against the covering 20.

When setting up the enclosure 10, the distal ends of the poles are inserted into the corresponding pockets at the corners of a selected sidewall panel 22, with the outer face 92 of the hub oriented facing outwardly, against the material of the sidewall. The hub is then pushed outwardly until it bows out past the corners of the sidewall 22, in a gently bowed configuration similar to an open, unfurled umbrella.

The Anchor Stakes

The portable enclosure 10 is maintained in contact with the ice or other substrate surface 5 using a plurality of anchor stakes 130 (FIG. 8) which cooperatively engage the through hole pair 66 formed in the skirt portions 50 at each corner of the portable enclosure 10 (FIG. 4). Each anchor stake 130 comprises an elongate shank 134.

The upper end of the shank 134 is shaped to form a handle 132. The handle is sized and shaped to allow adequate gripping and leverage for manual rotation of the anchor stake during use. In the illustrated embodiment, the handle is shaped to form an elongated loop, but it may also be formed in other shapes, including a T-shape. The handle may be provided with a insulative covering, such as rubber or a suitable elastomeric coating, for improved comfort and grippability when used in cold environments.

The lower end 138 of the shank 134 is tapered, and terminates in a pointed tip 140. For ease of threading into an ice surface 5, the tapered portion may be two inches or more in length. The lower end 138 is provided with coarse exterior threads 142, and at the tip 140 the shank 134 is provided with a generally helical shape, in the manner of a corkscrew. As a result, the tip 140 is oriented at an angle θ relative to the longitudinal axis of the shank 138 (FIG. 9). This configuration of the shank 134, wherein the outer surface is threaded and the tip 140 is angled, are features which allow the anchor stake 130 to be manually screwed into the surface 5 of the ice with only moderate effort.

Each anchor stake 130 is also provided with a flange 136 formed between the handle 132 and the lower end 138. The flange 136 is a thin plate extending in a direction normal to the longitudinal axis of the shank 134. The flange 136 has an outer diameter that is greater than the diameter of the reinforcing grommets 60 of the through holes 58 formed at each end 54 of the skirt portion 50. To prevent the flange 136 from passing through the grommets 60, the diameter of the flange 136 should be at least twice the diameter of the through holes formed in the grommets 60. In use, the lower end 138 of anchor stake 130 is inserted into a through hole pair 66 of the skirt portion 50, and is drawn into the surface of the substrate 5 by manually turning the handle 132. The flange 136 provides a stop surface when anchor stake 130 is sufficiently screwed into the ice, such that the layered ends 54, 54 of the skirt portion 50 are tightly sandwiched between the ice surface 5 and the flange 136. Use of a threaded anchor stake provides simple and quick securement to the ice surface, in contrast to a prior art method of chipping a hole for a stake, and adding water to freeze the stake therein.

Although the present invention has been described herein with respect to a number of specific illustrative embodiments, the foregoing description is intended to illustrate, rather than to limit the invention. Those skilled in the art will realize that many modifications of the preferred embodiment could be made which would be operable. All such modifications, which are within the scope of the claims, are intended to be within the scope and spirit of the present invention. 

1. A collapsible and portable enclosure for providing concealment to a user, the portable enclosure comprising: a fabric cover comprising at least one side wall, the fabric cover having at least one window opening formed through said side wall, a support structure for reinforcing said fabric cover; and a flexible panel extending across said at least one window opening, said flexible panel having a partially reflective exterior surface which reflects some light and transmits some light, whereby the flexible panel functions as a one-way mirror. 